Use MBString functions for 8bit data read

Prevents issues with MBString overrides of standard PHP functions.

Author: bsweeney

src/FontLib/EOT/File.php

@@ -74,8 +74,7 @@ public function read($n) {
     }
 
     $string = fread($this->f, $n);
-    $chunks = str_split($string, 2);
-    $chunks = array_map("strrev", $chunks);
+    $chunks = mb_str_split($string, 2, '8bit');
 
     return implode("", $chunks);
   }

src/FontLib/Table/DirectoryEntry.php

@@ -37,14 +37,14 @@ class DirectoryEntry extends BinaryStream {
   protected $origF;
 
   static function computeChecksum($data) {
-    $len = strlen($data);
+    $len = mb_strlen($data, '8bit');
     $mod = $len % 4;
 
     if ($mod) {
       $data = str_pad($data, $len + (4 - $mod), "\0");
     }
 
-    $len = strlen($data);
+    $len = mb_strlen($data, '8bit');
 
     $hi = 0x0000;
     $lo = 0x0000;

src/FontLib/TrueType/File.php

@@ -124,7 +124,7 @@ function parse() {
   }
 
   function utf8toUnicode($str) {
-    $len = strlen($str);
+    $len = mb_strlen($str, '8bit');
     $out = array();
 
     for ($i = 0; $i < $len; $i++) {

src/FontLib/WOFF/File.php

@@ -50,7 +50,7 @@ public function load($file) {
       }
 
       // Prepare data ...
-      $length        = strlen($data);
+      $length        = mb_strlen($data, '8bit');
       $entry->length = $entry->origLength = $length;
       $entry->offset = $dataOffset;